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# how to use glVertex with screen coordinates

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Hi!

I'm trying to convert the awt.Graphics.drawLine into OpenGL.

glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowSize(600, 300);
(void)glutCreateWindow("GLUT Program");


How can I use glVertex2i with screen coordinates. Something like.

glVertex2i(100, 100);


Meaning that it will draw something on position x=100, y=100 on my window screen of size (600, 300)

In java one can use awt.Graphics.drawLine with window coordinates.

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You can use gluOrtho2D() (if you want it to be 2D) to set the window coordinates to whatever you like.

gluOrtho2D (0, 600, 0, 300); for example would set the window coordinates to 0,0 at the bottom left, and 600,300 at the top right.

Could do something like this.
int width = 600;
int height = 300;
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowSize(width, height);
gluOrtho2D(0, width, 0, height);
(void)glutCreateWindow("GLUT Program");


The first parameter in gluOrtho2D is the value of the x-axis at the left, the second at the right. The third is the value of the y-axis at the bottom, the fourth at the top.

Hope that helped.

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